JPH08195715A - Optical transmission system - Google Patents
Optical transmission systemInfo
- Publication number
- JPH08195715A JPH08195715A JP7004861A JP486195A JPH08195715A JP H08195715 A JPH08195715 A JP H08195715A JP 7004861 A JP7004861 A JP 7004861A JP 486195 A JP486195 A JP 486195A JP H08195715 A JPH08195715 A JP H08195715A
- Authority
- JP
- Japan
- Prior art keywords
- optical
- light source
- optical signal
- signal
- polarization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
- H04B10/2572—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to forms of polarisation-dependent distortion other than PMD
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/06—Polarisation multiplex systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は光ＣＡＴＶ、光ＩＴＶ、
光伝送監視装置等の光伝送システムに関するものであ
る。The present invention relates to an optical CATV, an optical ITV,
The present invention relates to an optical transmission system such as an optical transmission monitoring device.
【０００２】[0002]
【従来の技術】光ＣＡＴＶ、光ＩＴＶ、光伝送監視装置
等の光伝送システムにおいて、波長の異なる複数光を合
波して多重伝送し、それを受信局で検波する場合、各光
の相互作用により発光波長（発光周波数）の差分が光ビ
ートとして検波出力に現れ、それが伝送品質を損なう大
きな要因となる。例えば、図６に示すような光伝送シス
テムにおいて、各発信局３１から送信される映像を一本
の光ファイバによって伝送する場合について説明する。2. Description of the Related Art In an optical transmission system such as an optical CATV, an optical ITV, an optical transmission monitor, etc., when a plurality of lights having different wavelengths are combined and multiplexed and then detected by a receiving station, the interaction of the lights As a result, the difference in emission wavelength (emission frequency) appears as an optical beat in the detection output, which becomes a major factor in impairing transmission quality. For example, in the optical transmission system as shown in FIG. 6, a case where an image transmitted from each transmitting station 31 is transmitted by one optical fiber will be described.
【０００３】各発信局３１から送信される信号例えば映
像を変調器３３によって強度変調を行い、この映像電気
信号をＥ／Ｏ変換器３５（例えばＬＤ）により光信号に
変換して光カプラ３７で合波して光伝送路３９に混入さ
せる。混入された光信号は受信局４１へ向かって進行
し、受信局４１の検波器４３（例えばＰＤ）で各発信局
３１から送信される複数の信号が電気信号に検波された
後に、分配器４５により分配され、復調器４７で復調さ
れてモニタ４９に映像が映し出される。A signal transmitted from each transmitting station 31, for example, a video is intensity-modulated by a modulator 33, and this video electrical signal is converted into an optical signal by an E / O converter 35 (for example, LD), and an optical coupler 37 is used. They are multiplexed and mixed in the optical transmission line 39. The mixed optical signal travels toward the receiving station 41, and after a plurality of signals transmitted from each transmitting station 31 are detected by the wave detector 43 (for example, PD) of the receiving station 41 as an electric signal, the distributor 45. The video is displayed on the monitor 49 by being demodulated by the demodulator 47.
【０００４】[0004]
【発明が解決しようとする課題】上述のように一本の光
伝送路に複数の光信号を合波して多重伝送するシステム
にあっては、光信号の相互干渉による光ビートが検波器
において発生する。この光ビートは光信号の波長差に応
じて発生する。通常、システム構築時には伝送帯域内の
光ビートレベルが伝送品質に大きな影響を与えないよう
に光波長を選択あるいは制御する。しかし、経時変化等
によって波長が当初のものと異なってしまった場合に、
光ビートが伝送帯域に影響を与えることになる。In the system for multiplexing a plurality of optical signals on a single optical transmission line as described above and performing multiplex transmission, an optical beat due to mutual interference of optical signals is detected in a detector. appear. This optical beat is generated according to the wavelength difference of the optical signal. Usually, when constructing a system, the optical wavelength is selected or controlled so that the optical beat level in the transmission band does not significantly affect the transmission quality. However, if the wavelength is different from the initial one due to changes over time,
The optical beat will affect the transmission band.
【０００５】検波器において発生する光ビートがＥ／Ｏ
変換器で発信している信号と同一周波数帯に発生した場
合には、信号の伝送品質（ノイズの増加）を著しく劣化
させる。ところで、従来例で述べたような一本の光ファ
イバの中に光信号を多重するようなシステム形態の場
合、一度多重した光信号がどの端局から送信されたもの
かを光信号レベルで分離することができない。そのた
め、伝送帯域に影響をあたえる光ビートがどの端局から
送信された光信号なのかを見分けることが困難である。
従って、発信局個別の特定を行うことが難しい。The optical beat generated in the detector is E / O
If it occurs in the same frequency band as the signal transmitted by the converter, the signal transmission quality (increase in noise) is significantly deteriorated. By the way, in the case of a system configuration in which an optical signal is multiplexed in one optical fiber as described in the conventional example, it is determined by the optical signal level from which end station the optical signal once multiplexed is transmitted. Can not do it. Therefore, it is difficult to distinguish from which end station the optical beat that affects the transmission band is the optical signal transmitted.
Therefore, it is difficult to identify each transmitting station.
【０００６】本発明は上記の課題を解決し、伝送帯域内
に発生する光ビートに関与している発信局を明らかに
し、その光ビートによる伝送品質の劣化を低減する光伝
送システムを提供することを目的とする。The present invention solves the above problems, clarifies a transmitting station which is involved in an optical beat generated in a transmission band, and provides an optical transmission system which reduces deterioration of transmission quality due to the optical beat. With the goal.
【０００７】[0007]
【課題を解決するための手段】本発明は上記の課題を解
決するために以下のような手段を有している。The present invention has the following means in order to solve the above problems.
【０００８】本発明のうち請求項１の光伝送システム
は、複数の発信局より変調された光信号がそれぞれ発信
されて一本の光ファイバに伝送され、これらの光信号が
受信局の検波器により同時に検波され復調されて分配さ
れる光伝送システムであって、前記検波器に光信号の光
源の波長差に応じて発生する光ビートの内で、前記光信
号を変調している電気信号の伝送帯域に影響を与える光
ビートの発生源となる発信局の光信号の光源を、前記複
数の発信局の光信号の光源の偏波を変化させて検知する
ことを特徴とする。In the optical transmission system according to claim 1 of the present invention, the modulated optical signals are respectively transmitted from a plurality of transmitting stations and transmitted to one optical fiber, and these optical signals are detected by the detector of the receiving station. Is an optical transmission system that is simultaneously detected, demodulated, and distributed by an optical beat that is generated in the detector according to the wavelength difference of the light source of the optical signal, and the electrical signal that modulates the optical signal It is characterized in that the light source of the optical signal of the transmitting station, which is the source of the optical beat affecting the transmission band, is detected by changing the polarization of the light source of the optical signals of the plurality of transmitting stations.
【０００９】本発明のうち請求項２の光伝送システム
は、光信号の光源の偏波を磁界により変化させて光信号
を変調している電気信号の伝送帯域に影響を与える光ビ
ートの発生源となる発信局の光信号の光源を検知するこ
とを特徴とする。The optical transmission system according to a second aspect of the present invention is an optical beat generation source that affects the transmission band of an electric signal that modulates the optical signal by changing the polarization of the light source of the optical signal by a magnetic field. It is characterized by detecting the light source of the optical signal of the transmitting station.
【００１０】本発明のうち請求項３の光伝送システム
は、複数の発信局の光信号の光源の偏波の変化は偏波面
変調器により行うことを特徴とする。The optical transmission system according to claim 3 of the present invention is characterized in that the polarization of the light source of the optical signals of a plurality of transmitting stations is changed by a polarization plane modulator.
【００１１】本発明のうち請求項４の光伝送システム
は、光信号の偏波を光ファイバに振動を加えて変化さ
せ、光信号を変調している電気信号の伝送帯域に影響を
与える光ビートの発生源となる発信局の光信号の光源を
検知することを特徴とする。According to a fourth aspect of the present invention, in the optical transmission system of the invention, the polarization of the optical signal is changed by applying vibration to the optical fiber to affect the transmission band of the electric signal that modulates the optical signal. It is characterized by detecting the light source of the optical signal of the transmitting station which is the generation source of.
【００１２】本発明のうち請求項５の光伝送システム
は、光信号を変調している電気信号の伝送帯域に影響を
与える光ビートの発生源となる発信局の光信号の光源
を、複数の発信局の光信号の光源の偏波を変化させて検
知し、前記検知した発信局の光信号の光源の波長を変え
ることによって光信号の光源の波長差に応じて発生する
光ビートを前記光信号の伝送帯域に影響を与えないよう
にすること特徴とする。According to a fifth aspect of the present invention, in the optical transmission system according to the fifth aspect, a plurality of optical signal light sources of the transmitting station, which are sources of optical beats affecting the transmission band of the electric signal modulating the optical signal, are provided. The optical beat is generated by changing the polarization of the light source of the optical signal of the transmitting station and changing the wavelength of the light source of the detected optical signal of the transmitting station to generate an optical beat according to the wavelength difference of the light source of the optical signal. The feature is that it does not affect the signal transmission band.
【００１３】本発明のうち請求項６の光伝送システム
は、複数の発信局と受信局が双方向光ファイバ回線を有
していて、複数の発信局の光信号の光源の偏波を変化さ
せる制御及び発信局の光信号の光源の波長を変える制御
を受信局から発信局への光ファイバ回線を用いて行い、
光信号の光源の偏波の変化の検知を前記複数の発信局か
ら受信局への光ファイバ回線を用いて行うこと特徴とす
る。In the optical transmission system according to claim 6 of the present invention, the plurality of transmitting stations and the receiving stations have bidirectional optical fiber lines, and change the polarization of the light source of the optical signals of the plurality of transmitting stations. Control and control to change the wavelength of the light source of the optical signal of the transmitting station, using the optical fiber line from the receiving station to the transmitting station,
The change in polarization of the light source of the optical signal is detected by using an optical fiber line from the plurality of transmitting stations to the receiving station.
【００１４】[0014]
【作用】本発明のうち請求項１の光伝送システムによれ
ば、複数の発信局より変調された光信号がそれぞれ発信
されて一本の光ファイバに伝送され、これらの光信号が
受信局の検波器により同時に検波され復調されて分配さ
れる光伝送システムであって、検波器に光信号の光源の
波長差に応じて発生する光ビートの内で、光信号を変調
している電気信号の伝送帯域に影響を与える光ビートの
発生源となる発信局の光信号の光源を、複数の発信局の
光信号の光源の偏波を変化させて検知することにより以
下のような作用を有する。According to the optical transmission system of claim 1 of the present invention, the modulated optical signals are respectively transmitted from a plurality of transmitting stations and transmitted to one optical fiber, and these optical signals are transmitted to the receiving station. An optical transmission system in which a wave is simultaneously detected by a wave detector, demodulated, and distributed, and in an optical beat generated according to the wavelength difference of the light source of the light signal in the wave detector, By detecting the light source of the optical signal of the transmitting station, which is the source of the optical beat that affects the transmission band, by changing the polarization of the light source of the optical signals of the plurality of transmitting stations, the following effects are obtained.
【００１５】光ビートの発生は光源の波長差によって決
定されると同時に、その光ビートレベルは図５に示すよ
うに、干渉し合う光ビートの偏波面の重なり具合に依存
している。従って、光信号の光源の偏波を変化させると
この変化に伴って光ビートレベルが変化する、この変化
の観測を行うことによってどの発信局が伝送帯域に影響
を及ぼす光ビートを発生させているかを検知することが
できる。すなわち、各発信局の光信号の光源の偏波を順
次変化させ受信局でその光ビートレベルを測定して、伝
送帯域に影響を及ぼす光ビートを発生させている発信局
の光信号の光源を見つけ出すことができる。The generation of the optical beat is determined by the wavelength difference of the light source, and at the same time, the optical beat level depends on the overlapping degree of the polarization planes of the interfering optical beats, as shown in FIG. Therefore, if the polarization of the light source of the optical signal is changed, the optical beat level changes with this change. By observing this change, which transmitter station is generating the optical beat that affects the transmission band? Can be detected. That is, the polarization of the light source of the optical signal of each transmitting station is sequentially changed, the optical beat level is measured at the receiving station, and the light source of the optical signal of the transmitting station generating the optical beat that affects the transmission band is set. You can find out.
【００１６】本発明のうち請求項２の光伝送システムに
よれば、光信号の光源の偏波を磁界により変化させるの
で、簡単な装置で光源の偏波を変化させることができ
る。According to the optical transmission system of the second aspect of the present invention, since the polarization of the light source of the optical signal is changed by the magnetic field, the polarization of the light source can be changed by a simple device.
【００１７】本発明のうち請求項３の光伝送システムに
よれば、複数の発信局の光信号の光源の偏波の変化は偏
波面変調器により行うので、簡単な装置で光源の偏波の
変化を行うことができる。According to the optical transmission system of claim 3 of the present invention, since the polarization of the light source of the optical signals of a plurality of transmitting stations is changed by the polarization plane modulator, the polarization of the light source can be changed by a simple device. Changes can be made.
【００１８】本発明のうち請求項４の光伝送システムに
よれば、光信号の偏波を光ファイバに振動を加えて変化
させるので、簡単な装置で光源の偏波の変化を変化させ
ることができる。また、光ファイバに加える振動の振動
数を各発信局毎に変えると各発信局の光源の偏波を同時
に変化させても、光ビートのレベル変動の周期から伝送
帯域内への光ビート発生に関与している発信局を検出す
ることが可能となる。According to the optical transmission system of claim 4 of the present invention, since the polarization of the optical signal is changed by applying vibration to the optical fiber, the change of the polarization of the light source can be changed with a simple device. it can. In addition, if the frequency of the vibration applied to the optical fiber is changed for each transmitting station, even if the polarization of the light source of each transmitting station is changed at the same time, the optical beat generation from the cycle of optical beat level fluctuations to the transmission band It is possible to detect the originating station involved.
【００１９】本発明のうち請求項５の光伝送システムに
よれば、光信号を変調している電気信号の伝送帯域に影
響を与える光ビートの発生源となる発信局の光信号の光
源を、複数の発信局の光信号の光源の偏波を変化させて
検知し、前記検知した発信局の光信号の光源の波長を変
えることによって光信号の光源の波長差に応じて発生す
る光ビートを前記光信号の伝送帯域に影響を与えないよ
うにするので、システム構築時には伝送帯域内の光ビー
トレベルが伝送品質に大きな影響を与えないように複数
の発信局の光信号の光源の光波長を選択して構築したも
のが、経時変化等によって波長が当初のものと異なって
伝送帯域内の光ビートレベルが伝送品質に大きな影響を
与えるようになった場合でも、検知した発信局の光信号
の光源の波長を変えることによって、システム構築時の
ように伝送帯域内の光ビートレベルが伝送品質に大きな
影響を与えないようにすることができる。According to the optical transmission system of claim 5 of the present invention, the light source of the optical signal of the transmitting station, which is a source of the optical beat affecting the transmission band of the electric signal which modulates the optical signal, An optical beat generated according to the wavelength difference of the light source of the optical signal is detected by changing the polarization of the light source of the optical signal of the plurality of transmitting stations and changing the wavelength of the light source of the optical signal of the detected transmitting station. Since it does not affect the transmission band of the optical signal, the optical wavelengths of the light sources of the optical signals of a plurality of transmission stations are set so that the optical beat level in the transmission band does not greatly affect the transmission quality when the system is constructed. Even if the selected and constructed one has a wavelength different from the original one due to aging etc. and the optical beat level in the transmission band has a great influence on the transmission quality, the detected optical signal of the transmitting station Change the wavelength of the light source By Rukoto, optical beat level in a transmission band such as during system construction can be prevented significantly affect the transmission quality.
【００２０】本発明のうち請求項６の光伝送システムに
よれば、複数の発信局と受信局が双方向光ファイバ回線
を有していて、複数の発信局の光信号の光源の偏波を変
化させる制御及び発信局の光信号の光源の波長を変える
制御を受信局から発信局への光ファイバ回線を用いて行
い、光信号の光源の偏波の変化の検知を前記複数の発信
局から受信局への光ファイバ回線を用いて行うので、受
信局で一括して各発信局の光信号の光源の偏波を変化さ
せることができるとともに、各発信局の光信号の光源の
波長を変化させることもできる。According to the optical transmission system of the sixth aspect of the present invention, the plurality of transmitting stations and the receiving stations have bidirectional optical fiber lines, and the polarization of the light source of the optical signal of the plurality of transmitting stations is controlled. The control for changing and the control for changing the wavelength of the light source of the optical signal of the transmitting station are performed using the optical fiber line from the receiving station to the transmitting station, and the change of the polarization of the light source of the optical signal is detected from the plurality of transmitting stations. Since the optical fiber line to the receiving station is used, the receiving station can change the polarization of the light source of the optical signal of each transmitting station at the same time, and the wavelength of the light source of the optical signal of each transmitting station can be changed. You can also let it.
【００２１】[0021]
【実施例】以下に本発明を実施例により詳細に説明す
る。The present invention will be described below in detail with reference to examples.
【００２２】（実施例１）本発明の光伝送システムの一
実施例を図１及び図２を参照して説明する。各発信局１
から送信される信号例えば映像を変調器２によって強度
変調を行い、この映像電気信号をＥ／Ｏ変換器３（例え
ばＬＤ）により光信号に変換して光カプラ４で合波して
光伝送路５に混入させる。混入された光信号は受信局６
へ向かって進行し、受信局６の検波器７（例えばＰＤ）
で各発信局１から送信される複数の信号が電気信号に検
波された後に、分配器８により分配され、復調器９で復
調されてモニタ１０に映像が映し出されることは従来と
同様である。(Embodiment 1) An embodiment of the optical transmission system of the present invention will be described with reference to FIGS. Each originating station 1
A signal transmitted from the device, for example, an image is intensity-modulated by a modulator 2, and this image electric signal is converted into an optical signal by an E / O converter 3 (for example, LD) and combined by an optical coupler 4 to form an optical transmission line. Mix in 5. The mixed optical signal is received by the receiving station 6
Towards the detector 7 of the receiving station 6 (eg PD)
In the same manner as in the prior art, after a plurality of signals transmitted from each transmitting station 1 are detected as electric signals, the signals are distributed by the distributor 8, demodulated by the demodulator 9 and displayed on the monitor 10.
【００２３】本発明にあっては発信局１は図２に示すよ
うに光源即ちＥ／Ｏ変換器３から発信される光信号がフ
ァラデ素子からなる偏波面偏光器３Ａによって偏波面の
変調が行われる。偏波面偏光器３Ａの両側には磁局（磁
界発生箇所）１６が配置されている。この磁局１６に磁
界を発生させるとファラデ素子からなる偏波面偏光器３
Ａの偏波面が変化する。光ビートのピークレベルは干渉
し合う光の偏波面の角度によって決定され、直線偏波光
信号同上の場合には相互確度の関係が直交した場合に殆
ど皆無となる。In the present invention, as shown in FIG. 2, in the transmitting station 1, the optical signal transmitted from the light source, that is, the E / O converter 3 is modulated in the plane of polarization by the polarization plane polarizer 3A composed of a Faraday element. Be seen. Magnetic stations (magnetic field generation points) 16 are arranged on both sides of the polarization plane polarizer 3A. When a magnetic field is generated in this magnetic station 16, a polarization plane polarizer 3 including a Faraday element is formed.
The plane of polarization of A changes. The peak level of the optical beat is determined by the angle of the planes of polarization of the lights that interfere with each other, and in the case of the linearly polarized light signal, the linear accuracy of the optical signal is almost zero when the mutual accuracy relationships are orthogonal.
【００２４】例えば、発信局１Ａの光信号のＥ／Ｏ変換
器３が光信号の伝送帯域に影響を与えている光ビートの
発生源である場合について説明する。発信局１Ａを含む
各発信局１のＥ／Ｏ変換器３から光信号が光カプラ４を
介して光伝送路５へ送信される。かかる複数の光信号は
検波器７によって同時に検波され復調器９へ入力され
る。この際、検波器７において発信局１Ａの光信号のＥ
／Ｏ変換器３が係わる光の波長差分に相当する周波数に
光の相互干渉による光ビートが発生する。For example, the case where the E / O converter 3 for the optical signal of the transmitting station 1A is the source of the optical beat affecting the transmission band of the optical signal will be described. An optical signal is transmitted from the E / O converter 3 of each transmitting station 1 including the transmitting station 1A to the optical transmission line 5 via the optical coupler 4. The plurality of optical signals are simultaneously detected by the detector 7 and input to the demodulator 9. At this time, in the detector 7, E of the optical signal of the transmitting station 1A
An optical beat is generated by mutual interference of light at a frequency corresponding to the wavelength difference of light related to the / O converter 3.
【００２５】ここで、発信局１Ａの磁局１６に磁界を発
生させてファラデ素子からなる偏波面偏光器３Ａの偏波
面を変化させると、検波器７でその光ビートレベルが変
化するので、偏波面偏光器３Ａの偏波面を変化させた発
信局１Ａの光信号のＥ／Ｏ変換器３の波長が光信号の伝
送帯域に影響を与えている光ビート発生源であることを
検波器７によって検知することができる。また、発信局
１Ａの光信号のＥ／Ｏ変換器３が光信号の伝送帯域に影
響を与えている光ビートの発生源でない場合は、それぞ
れの発信局１の磁局１６に磁界を発生させることを順次
行っていくことによって光ビートレベルの変化が観測さ
れた発信局１が伝送帯域に影響を与えていることが分か
る。その後、当発信局１のＥ／Ｏ変換器３の波長を制御
して伝送帯域に影響の無い帯域まで光ビートの中心波長
をずらすことによって伝送品質の劣化（光ビートの増
加）を改善することができる。Here, when a magnetic field is generated in the magnetic station 16 of the transmitting station 1A to change the polarization plane of the polarization plane polarizer 3A composed of Farade elements, the optical beat level of the detector 7 changes, so By the detector 7, it is determined that the wavelength of the E / O converter 3 of the optical signal of the transmission station 1A, which has changed the polarization plane of the wavefront polarizer 3A, is an optical beat generation source that affects the transmission band of the optical signal. Can be detected. If the E / O converter 3 of the optical signal of the transmitting station 1A is not the source of the optical beat affecting the transmission band of the optical signal, the magnetic station 16 of each transmitting station 1 is caused to generate a magnetic field. It can be seen that the transmitting station 1 in which the change in the optical beat level is observed affects the transmission band by sequentially performing the above steps. After that, by controlling the wavelength of the E / O converter 3 of the transmitting station 1 and shifting the central wavelength of the optical beat to a band that does not affect the transmission band, deterioration of transmission quality (increase of optical beat) is improved. You can
【００２６】（実施例２）本発明の光伝送システムの他
の実施例を図３を参照して説明する。各発信局１から送
信される信号例えば映像を変調器２によって強度変調を
行い、この映像電気信号をＥ／Ｏ変換器３（例えばＬ
Ｄ）により光信号に変換して光カプラ４で合波して光伝
送路５に混入させる。混入された光信号は受信局６へ向
かって進行し、受信局６の検波器７（例えばＰＤ）で各
発信局１から送信される複数の信号が電気信号に検波さ
れた後に、分配器８により分配され、復調器９で復調さ
れてモニタ１０に映像が映し出されることは実施例１と
同様である。尚、各発信局１は同一の構成につき一つの
み図示し他の図については詳細な図示は省略してある。(Embodiment 2) Another embodiment of the optical transmission system of the present invention will be described with reference to FIG. A signal transmitted from each transmitting station 1, for example, a video is intensity-modulated by a modulator 2, and the video electrical signal is E / O converter 3 (for example, L
It is converted into an optical signal by D), multiplexed by the optical coupler 4 and mixed in the optical transmission line 5. The mixed optical signal travels toward the receiving station 6, and after a plurality of signals transmitted from each transmitting station 1 are detected by the wave detector 7 (for example, PD) of the receiving station 6 into electric signals, the distributor 8 The image is displayed on the monitor 10 by being demodulated by the demodulator 9 as in the first embodiment. It should be noted that only one transmitting station 1 is shown for the same configuration, and detailed illustration is omitted for the other drawings.
【００２７】本実施例の特徴は受信局６の復調器９で復
調された信号を光ビート検出系１１に設けられたバンド
パスフィルタ１２及びパワーメータ１３によってサブキ
ャリヤ周波数帯域の光ビートレベルを常時観測する点に
ある。光ビートレベルがある規定値よりも高くなった場
合には、光ビート検出系１１から制御系１４にアラーム
が出される。それを受けた制御系１４は、各発信局１の
Ｅ／Ｏ変換器３に設置された磁局１６の駆動信号を下り
光伝送路５Ａに載せて送信する。受信局６から送信され
る信号は変調器２Ａによって強度変調を行い、この電気
信号をＥ／Ｏ変換器３Ｂ（例えばＬＤ）により光信号に
変換して下り光伝送路５Ａで送信する。The feature of this embodiment is that the signal demodulated by the demodulator 9 of the receiving station 6 is constantly kept at the optical beat level in the subcarrier frequency band by the bandpass filter 12 and the power meter 13 provided in the optical beat detection system 11. It is at the point of observation. When the optical beat level becomes higher than a predetermined value, the optical beat detection system 11 issues an alarm to the control system 14. The control system 14 having received it transmits the drive signal of the magnetic station 16 installed in the E / O converter 3 of each transmitting station 1 on the downstream optical transmission line 5A. The signal transmitted from the receiving station 6 is intensity-modulated by the modulator 2A, and this electric signal is converted into an optical signal by the E / O converter 3B (for example, LD) and transmitted through the downstream optical transmission line 5A.
【００２８】この下り光伝送路５Ａに載せて送信された
駆動信号は各光カプラ４Ａで分波され各発信局１の検波
器７Ａ（例えばＰＤ）で検波される。図中９Ａは復調器
であある。この下り光伝送路５Ａに載せて送信された駆
動信号によって各発信局１の磁局１６が順次磁界を発生
させてファラデ素子からなる偏波面偏光器３Ａの偏波面
の変動がおこり、その発信局１に設定された光ビートレ
ベルが変化するので、受信局６においてどの発信局１が
帯域内に発生した光ビートに関与しているかが明確にな
る。The drive signal transmitted on the downstream optical transmission line 5A is demultiplexed by each optical coupler 4A and detected by the detector 7A (eg PD) of each transmitting station 1. In the figure, 9A is a demodulator. The magnetic field 16 of each transmitting station 1 sequentially generates a magnetic field by the drive signal transmitted on the downstream optical transmission line 5A, and the polarization plane of the polarization plane polarizer 3A composed of Farade elements fluctuates. Since the optical beat level set to 1 changes, it becomes clear in the receiving station 6 which transmitting station 1 is involved in the optical beat generated in the band.
【００２９】帯域内に発生した光ビートに関与している
発信局１が明確になった後、その発信局１あてに再び下
り光伝送路５Ａでその発信局１のＥ／Ｏ変換器３の発信
温度の温度制御信号を送り、光ビートの中心波長が伝送
帯域からずれるように設定する。つまり光源の発信中心
波長が発信温度で変わることを利用したものである。図
中１５は各発信局１に設けられた磁局１６の制御系であ
る。After the transmitting station 1 involved in the optical beat generated in the band is clarified, the transmitting station 1 is again directed to the E / O converter 3 of the transmitting station 1 through the downstream optical transmission line 5A. A temperature control signal for the transmission temperature is sent and the center wavelength of the optical beat is set so as to deviate from the transmission band. In other words, it utilizes the fact that the center wavelength of the light emitted from the light source changes depending on the transmission temperature. In the figure, reference numeral 15 is a control system of the magnetic station 16 provided in each transmitting station 1.
【００３０】尚、上記の光源の発信中心波長の制御は発
信温度を変えることによって行ったが中心波長の制御は
発信温度を変えるやり方に限るものではなく例えば可変
波長光源を使用するやり方でもよい。Although the control of the transmission center wavelength of the light source is performed by changing the transmission temperature, the control of the center wavelength is not limited to the method of changing the transmission temperature, and for example, a variable wavelength light source may be used.
【００３１】（実施例３）実施例１及び実施例２におい
ては発信局の磁局に磁界を発生させてファラデ素子から
なる偏波面偏光器で偏波面を変化させているが、偏波面
を変化させる方法は磁局に磁界を発生させて偏波面を変
化させる方法に限らず、例えば図４に示すように光ファ
イバに振動を加えて偏波面を変化させる偏波面変調器３
Ｄのような装置を用いることも可能である。図４におい
て３Ｃは偏波面変調器３Ｄに振動信号を送る偏波面変調
器用ＳＧである。その他の機能は実施例２と同様につき
詳細な説明は省略する。このように、光ファイバに加え
る振動の振動数を各発信局毎に変えると各発信局の光源
の偏波を同時に変化させても、光ビートのレベル変動の
周期から伝送帯域内への光ビート発生に関与している発
信局を検出することが可能となる。(Embodiment 3) In Embodiments 1 and 2, the magnetic field is generated in the magnetic station of the transmitting station to change the polarization plane by the polarization plane polarizer composed of the Farade element, but the polarization plane is changed. The method is not limited to the method of generating a magnetic field in the magnetic station to change the plane of polarization. For example, as shown in FIG. 4, a polarization plane modulator 3 that vibrates an optical fiber to change the plane of polarization is used.
It is also possible to use a device such as D. In FIG. 4, reference numeral 3C is a polarization modulator SG that sends a vibration signal to the polarization modulator 3D. The other functions are similar to those of the second embodiment, and detailed description thereof will be omitted. In this way, if the frequency of the vibration applied to the optical fiber is changed for each transmitting station, even if the polarization of the light source of each transmitting station is changed at the same time, the optical beat from the cycle of optical beat level fluctuations to the transmission band It is possible to detect the originating station involved in the occurrence.
【００３２】[0032]
【発明の効果】以上述べたように、本発明のうち請求項
１の光伝送システムによれば、複数の発信局より変調さ
れた光信号がそれぞれ発信されて一本の光ファイバに伝
送され、これらの光信号が受信局の検波器により同時に
検波され復調されて分配される光伝送システムであっ
て、検波器に光信号の光源の波長差に応じて発生する光
ビートの内で、光信号を変調している電気信号の伝送帯
域に影響を与える光ビートの発生源となる発信局の光信
号の光源を、複数の発信局の光信号の光源の偏波を変化
させて検知することにより以下のような効果を有する。As described above, according to the optical transmission system of claim 1 of the present invention, the modulated optical signals are respectively transmitted from a plurality of transmitting stations and transmitted to one optical fiber, An optical transmission system in which these optical signals are simultaneously detected by the detector of the receiving station, demodulated and distributed, and the optical signal is generated within the optical beat generated according to the wavelength difference of the light source of the optical signal in the detector. By detecting the light source of the optical signal of the transmitting station that is the source of the optical beat that affects the transmission band of the electrical signal that is modulating the It has the following effects.
【００３３】光信号の光源の偏波を変化させるとこの変
化に伴って光ビートレベルが変化する、この変化の観測
を行うことによってどの発信局が伝送帯域に影響を及ぼ
す光ビートを発生させているかを検知することができ
る。すなわち、各発信局の光信号の光源の偏波を順次変
化させ受信局でその光ビートレベルを測定して、伝送帯
域に影響を及ぼす光ビートを発生させている発信局の光
信号の光源を見つけ出すことができる。When the polarization of the light source of the optical signal is changed, the optical beat level changes in accordance with this change. By observing this change, which transmitting station generates an optical beat that affects the transmission band. It can detect whether or not. That is, the polarization of the light source of the optical signal of each transmitting station is sequentially changed, the optical beat level is measured at the receiving station, and the light source of the optical signal of the transmitting station generating the optical beat that affects the transmission band is set. You can find out.
【００３４】本発明のうち請求項２の光伝送システムに
よれば、光信号の光源の偏波を磁界により変化させるの
で、簡単な装置で光源の偏波を変化させることができ
る。According to the optical transmission system of the second aspect of the present invention, since the polarization of the light source of the optical signal is changed by the magnetic field, the polarization of the light source can be changed with a simple device.
【００３５】本発明のうち請求項３の光伝送システムに
よれば、複数の発信局の光信号の光源の偏波の変化は偏
波面変調器により行うので、簡単な装置で光源の偏波の
変化を行うことができる。According to the optical transmission system of claim 3 of the present invention, since the polarization of the light source of the optical signals of the plurality of transmitting stations is changed by the polarization plane modulator, the polarization of the light source can be changed by a simple device. Changes can be made.
【００３６】本発明のうち請求項４の光伝送システムに
よれば、光信号の偏波を光ファイバに振動を加えて変化
させるので、簡単な装置で光源の偏波の変化を変化させ
ることができる。また、光ファイバに加える振動の振動
数を各発信局毎に変えると各発信局の光源の偏波を同時
に変化させても、光ビートのレベル変動の周期から伝送
帯域内への光ビート発生に関与している発信局を検出す
ることが可能となる。According to the optical transmission system of claim 4 of the present invention, since the polarization of the optical signal is changed by applying vibration to the optical fiber, the change of the polarization of the light source can be changed with a simple device. it can. In addition, if the frequency of the vibration applied to the optical fiber is changed for each transmitting station, even if the polarization of the light source of each transmitting station is changed at the same time, the optical beat generation from the cycle of optical beat level fluctuations to the transmission band It is possible to detect the originating station involved.
【００３７】本発明のうち請求項５の光伝送システムに
よれば、光信号を変調している電気信号の伝送帯域に影
響を与える光ビートの発生源となる発信局の光信号の光
源を、複数の発信局の光信号の光源の偏波を変化させて
検知し、前記検知した発信局の光信号の光源の波長を変
えることによって光信号の光源の波長差に応じて発生す
る光ビートを前記光信号の伝送帯域に影響を与えないよ
うにするので、システム構築時には伝送帯域内の光ビー
トレベルが伝送品質に大きな影響を与えないように複数
の発信局の光信号の光源の光波長を選択して構築したも
のが、経時変化等によって波長が当初のものと異なって
伝送帯域内の光ビートレベルが伝送品質に大きな影響を
与えるようになった場合でも、検知した発信局の光信号
の光源の波長を変えることによって、システム構築時の
ように伝送帯域内の光ビートレベルが伝送品質に大きな
影響を与えないようにすることができる。According to the optical transmission system of claim 5 of the present invention, the light source of the optical signal of the transmitting station, which is the source of the optical beat affecting the transmission band of the electric signal modulating the optical signal, is provided. An optical beat generated according to the wavelength difference of the light source of the optical signal is detected by changing the polarization of the light source of the optical signal of the plurality of transmitting stations and changing the wavelength of the light source of the optical signal of the detected transmitting station. Since it does not affect the transmission band of the optical signal, the optical wavelengths of the light sources of the optical signals of a plurality of transmission stations are set so that the optical beat level in the transmission band does not greatly affect the transmission quality when the system is constructed. Even if the selected and constructed one has a wavelength different from the original one due to aging etc. and the optical beat level in the transmission band has a great influence on the transmission quality, the detected optical signal of the transmitting station Change the wavelength of the light source By Rukoto, optical beat level in a transmission band such as during system construction can be prevented significantly affect the transmission quality.
【００３８】本発明のうち請求項６の光伝送システムに
よれば、複数の発信局と受信局が双方向光ファイバ回線
を有していて、複数の発信局の光信号の光源の偏波を変
化させる制御及び発信局の光信号の光源の波長を変える
制御を受信局から発信局への光ファイバ回線を用いて行
い、光信号の光源の偏波の変化の検知を前記複数の発信
局から受信局への光ファイバ回線を用いて行うので、受
信局で一括して各発信局の光信号の光源の偏波を変化さ
せることができるとともに、各発信局の光信号の光源の
波長を変化させることもできる。According to the optical transmission system of the sixth aspect of the present invention, the plurality of transmitting stations and the receiving stations have bidirectional optical fiber lines, and the polarization of the light source of the optical signal of the plurality of transmitting stations is controlled. The control for changing and the control for changing the wavelength of the light source of the optical signal of the transmitting station are performed using the optical fiber line from the receiving station to the transmitting station, and the change of the polarization of the light source of the optical signal is detected from the plurality of transmitting stations. Since the optical fiber line to the receiving station is used, the receiving station can change the polarization of the light source of the optical signal of each transmitting station at the same time, and the wavelength of the light source of the optical signal of each transmitting station can be changed. You can also let it.
【図１】本発明の光伝送システムの一実施例を示す説明
図である。FIG. 1 is an explanatory diagram showing an embodiment of an optical transmission system of the present invention.
【図２】図１の発信局のの説明図である。2 is an explanatory diagram of a transmitting station in FIG. 1. FIG.
【図３】本発明の光伝送システムの他の実施例を示す説
明図である。FIG. 3 is an explanatory diagram showing another embodiment of the optical transmission system of the present invention.
【図４】本発明の光伝送システムのさらに他の実施例を
示す説明図である。FIG. 4 is an explanatory diagram showing still another embodiment of the optical transmission system of the present invention.
【図５】偏波面の変化にともなう光ビートレベルの変化
の概念を示す説明図である。FIG. 5 is an explanatory diagram showing the concept of changes in optical beat level due to changes in polarization plane.
【図６】従来の光伝送システムの一例を示す説明図であ
る。FIG. 6 is an explanatory diagram showing an example of a conventional optical transmission system.
１ 発信局 １Ａ 発信局 ２ 変調器 ３ Ｅ／Ｏ変換器 ３Ａ 偏波面偏光器 ３Ｄ 偏波面変調器 ４ 光カプラ ５ 光伝送路 ６ 受信局 ７ 検波器 ８ 分配器 ９ 復調器 １０ モニタ １６ 磁局 1 Transmitting Station 1A Transmitting Station 2 Modulator 3 E / O Converter 3A Polarization Plane Polarizer 3D Polarization Plane Modulator 4 Optical Coupler 5 Optical Transmission Line 6 Receiver Station 7 Detector 8 Distributor 9 Demodulator 10 Monitor 16 Magnetic Station
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０４Ｊ 14/02 Ｈ０４Ｂ 10/152 10/142 10/04 10/06 Ｈ０４Ｂ 9/00 Ｌ (72)発明者 篠田 雪久 神奈川県横浜市鶴見区江ヶ崎町４番１号 東京電力株式会社システム研究所内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI technical display location H04J 14/02 H04B 10/152 10/142 10/04 10/06 H04B 9/00 L (72) Inventor Yukihisa Shinoda 4-1, Egasaki-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture
Claims (6)
れぞれ発信されて一本の光ファイバに伝送され、これら
の光信号が受信局の検波器により同時に検波され復調さ
れて分配される光伝送システムであって、前記検波器に
光信号の光源の波長差に応じて発生する光ビートの内
で、前記光信号を変調している電気信号の伝送帯域に影
響を与える光ビートの発生源となる発信局の光信号の光
源を、前記複数の発信局の光信号の光源の偏波を変化さ
せて検知することを特徴とする光伝送システム。1. An optical signal in which modulated optical signals are respectively transmitted from a plurality of transmitting stations and transmitted to one optical fiber, and these optical signals are simultaneously detected by a detector of a receiving station and demodulated and distributed. In the transmission system, an optical beat generation source that influences a transmission band of an electric signal that modulates the optical signal, in an optical beat generated in the detector according to a wavelength difference of a light source of the optical signal. The optical transmission system is characterized by detecting the light source of the optical signal of the transmitting station by changing the polarization of the light source of the optical signal of the plurality of transmitting stations.
せて光信号を変調している電気信号の伝送帯域に影響を
与える光ビートの発生源となる発信局の光信号の光源を
検知することを特徴とする請求項１記載の光伝送システ
ム。2. A light source of an optical signal of a transmitting station, which is a source of an optical beat that affects the transmission band of an electric signal that modulates the optical signal by changing the polarization of the light source of the optical signal by a magnetic field, is detected. The optical transmission system according to claim 1, wherein:
化は偏波面変調器により行うことを特徴とする請求項１
記載の光伝送システム。3. The polarization plane modulator is used to change the polarization of the light source of the optical signals of the plurality of transmitting stations.
The optical transmission system described.
て変化させ、光信号を変調している電気信号の伝送帯域
に影響を与える光ビートの発生源となる発信局の光信号
の光源を検知することを特徴とする請求項１又は請求項
３記載の光伝送システム。4. The optical signal of a transmitting station, which is a source of an optical beat that changes the polarization of an optical signal by applying vibration to an optical fiber to affect the transmission band of an electric signal that modulates the optical signal. The optical transmission system according to claim 1 or 3, wherein a light source is detected.
域に影響を与える光ビートの発生源となる発信局の光信
号の光源を、複数の発信局の光信号の光源の偏波を変化
させて検知し、前記検知した発信局の光信号の光源の波
長を変えることによって光信号の光源の波長差に応じて
発生する光ビートを前記光信号の伝送帯域に影響を与え
ないようにすること特徴とする請求項１乃至請求項４記
載の光伝送システム。5. A light source of an optical signal of a transmitting station, which is a source of an optical beat that affects a transmission band of an electric signal which modulates the optical signal, and a polarization of light sources of the optical signals of a plurality of transmitting stations. Detecting by changing, the optical beat generated according to the wavelength difference of the light source of the optical signal by changing the wavelength of the light source of the detected optical signal of the transmitting station, so as not to affect the transmission band of the optical signal The optical transmission system according to claim 1, wherein:
バ回線を有していて、複数の発信局の光信号の光源の偏
波を変化させる制御及び発信局の光信号の光源の波長を
変える制御を受信局から発信局への光ファイバ回線を用
いて行い、光信号の光源の偏波の変化の検知を前記複数
の発信局から受信局への光ファイバ回線を用いて行うこ
と特徴とする請求項５記載の光伝送システム。6. A control for changing the polarization of a light source of an optical signal of a plurality of transmitting stations and a wavelength of a light source of an optical signal of the transmitting station, wherein the plurality of transmitting stations and the receiving station have bidirectional optical fiber lines. Is controlled by using the optical fiber line from the receiving station to the transmitting station, and the change in the polarization of the light source of the optical signal is detected by using the optical fiber line from the plurality of transmitting stations to the receiving station. The optical transmission system according to claim 5.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7004861A JP2851247B2 (en) | 1995-01-17 | 1995-01-17 | Optical transmission system |
| DE19600982A DE19600982A1 (en) | 1995-01-17 | 1996-01-12 | Optical transmission system for video images |
| US08/587,574 US5767996A (en) | 1995-01-17 | 1996-01-17 | Optical transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7004861A JP2851247B2 (en) | 1995-01-17 | 1995-01-17 | Optical transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08195715A true JPH08195715A (en) | 1996-07-30 |
| JP2851247B2 JP2851247B2 (en) | 1999-01-27 |
Family
ID=11595465
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7004861A Expired - Lifetime JP2851247B2 (en) | 1995-01-17 | 1995-01-17 | Optical transmission system |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5767996A (en) |
| JP (1) | JP2851247B2 (en) |
| DE (1) | DE19600982A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6108113A (en) * | 1995-12-29 | 2000-08-22 | Mci Communications Corporation | Method and system for transporting ancillary network data |
| JP2002261696A (en) * | 2001-03-05 | 2002-09-13 | Mitsubishi Electric Corp | Optical signal distributer |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3014580B2 (en) * | 1994-02-17 | 2000-02-28 | 古河電気工業株式会社 | Optical transmission method |
| JP3323690B2 (en) * | 1995-03-15 | 2002-09-09 | ケイディーディーアイ株式会社 | Optical wavelength division multiplexing communication equipment |
-
1995
- 1995-01-17 JP JP7004861A patent/JP2851247B2/en not_active Expired - Lifetime
-
1996
- 1996-01-12 DE DE19600982A patent/DE19600982A1/en not_active Withdrawn
- 1996-01-17 US US08/587,574 patent/US5767996A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US5767996A (en) | 1998-06-16 |
| JP2851247B2 (en) | 1999-01-27 |
| DE19600982A1 (en) | 1996-07-18 |
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